1. Field of the Invention
The present invention relates to a variable length decoding of H.264/Advanced Video Coding (AVC) video decoder, and more particularly, to a method for referring fast a context-based adaptive variable length coding (CAVLC) table prescribed by a H.264/AVC standard.
2. Discussion of the Related Art
A digital multimedia broadcasting (DMB) video standard conforms to a H.264/AVC standard.
The video standard relates to a video bitstream syntax and a decoder. The DMB video decoder according to this standard uses two variable length coding types for efficient data bit assignment.
According to this standard, a Universal Variable Length Coding (UVLC) type is used for data except transformed coefficients of video data and a CAVLC type is used for transformed coefficients of video data.
The variable length coding type is a coding type for assigning the number of bits having a different length to a symbol of each signal depending on statistical characteristics of signal generation frequency using statistical characteristics of a signal. The variable length coding type is constantly used in a related art video compression method.
The CAVLC type prescribed by the H.264/AVC standard adopts a method for decoding a signal using a table that corresponds to variables such as TotalCoeff, TrailingOnes, total_zero, run_before depending on transformed coefficient characteristics of video data.
A related art method for performing the variable length decoding uses a method for reading a code that corresponds to a code length defined by the variable length decoding table from a bitstream to compare the code with a code of the variable length decoding table.
For the worst case, all code values of the table should be compared in order to apply this method, thus a process for accessing a bitstream memory in succession is required. Therefore, there has been a problem that a process speed of the decoder is lowered due to the above-described inefficient process.